Magnetic snap action switch



May 27, 1969 A. DOTTO 3,447,110

MAGNETIC SNAP ACTION SWITCH Filed Dec. 23, 1966 39 T 38 l l6 l2 I5 |4a l4 37 2 15a I ZZmFz INVENTOR GIANNI A. DOTTO ATTORNEY United States Patent U.S. Cl. 335-207 Claims 7 ABSTRACT OF THE DISCLOSURE A pair of magnets, one each disposed on a contact blade and an actuator blade of a double throw switch are constructed and arranged such that they repel each other as the magnet on the actuator blade is re'ciprocated past the magnet on the contact blade.

' In recent years there has been developed a number of snap action switches which utilize magnetic means to cause the opening and closing of the circuit through the use of the magnetic forces of attraction and repulsion. While these switches have, for the most part, been extremely useful they have not been without their problems. Among these problems are that of unsure making and breaking of the contact, misalignment of the magnets which retards the full utilization of the magnetic forces, and complicated mechanical linkage associated with the magnets. This is particularly true where the magnetic switch is of the double throw variety.

Accordingly, it is an object of the present invention to provide a snap action switch of the double throw variety.

Another object of the invention is to provide a double throw snap action switch wherein magnetic means are used to actuate the contact blade.

Still another object of the invention is to provide a magnetically operated double throw switch which is simply constructed and reliable in operation.

Yet another object of the invention is to provide a magnetically operated double throw switch wherein a magnet is disposed on the switch contact blade and anotherrnagnet is disposed on the switch actuating blade.

Another object of the invention is the provision of a magnetically operated double throw switch wherein the opposing faces of the two magnets are of the same polarity. I

Still another object of the invention is the provision of a magnetically operated double throw switch wherein movement of the switch contact blade is made in accordance with the opposing forces of the magnets.

With the above and other objects in view which will appear as the description proceeds, this invention resides in a novel magnetically operated double throw switch substantially as described herein and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the invention here disclosed may be made as come within the scope of the claims.

In the accompanying drawings:

FIGURE 1 is a cross section of a double throw switch showing the novel arrangement of the magnetic actuating means.

' FIGURE 2 is a cross-section of the double throw switch showing the novel magnetic means in a different position, and

FIGURE 3 is an exploded view showing the relationship of the switch contact blade and the switch actuating blade.

Generally speaking, -the objects of the invention are accomplished by providing a pair of magnets one of which is positioned on a snap acting actuator blade, the magnets being polarized and arranged such that they repel one another as the magnet of the actuator blade is reciprocated past the magnet of the contact blade thereby causing the contact blade to alternately reciprocate between the electrical contacts of the switch electrical terminals.

More particularly, in the present invention, as the actuator blade reciprocates, the magnet on the actuator blade repels the magnet disposed on the electrical contact blade as the actuator blade magnet approaches it. As the actuator blade begins to pass the midway point of the contact blade, the forces acting between the magnets causes the contact magnet to be repelled from the actuator magnet in the opposite direction. Thus as the actuator blade magnet reciprocates past the contact blade magnet, the contact blade magnet reciprocates oppositely from the actuator blade magnet due to the repelling force between the magnets.

With particular refernce now to FIGURES 1 and 3, the reference numeral 10 designates, generally, a snap acting switch. The switch 10 includes an elongated housing 11 formed of two sections 12 and 13, both of which are generally cup-shaped. Section 13 is provided with extensions 14 and 15, each having flanges 14a and 15a for fixedly holding the two sections together. Section 12 has an opening 16 through which a biasing means 17 is extended to bias actuator 18 in a manner hereinafter described.

At one end of the housing 11, there is shown a spacer 19 through which a pair of stationary electrical terminals 20 and 21 are extended in spaced parallel relation into the continuous cavity 22 formed by the housing 11. The housing 11, the spacer 19, actuator 18, and biasing means 17 are all constructed of a molded electrically insulating material such as a plastic compound of phenolic condensation product..At the opposed end of the housing 11, a single stationary electrical terminal 23 is shown extending into the cavity 22. Terminal 23 is formed from a snap acting electrical contact blade 24 and a snap acting actuator blade 25, the blade 25 being fixedly connected to actuator 18. The two blades are substantially contiguous from an area just inside the cavity 22 to the end 26 of the terminal, thus rendering a single unitary construction of a desired thickness.

The relationship of the blades and their construction can more readily be seen with particular reference to FIGURE 3 wherein there is shown the electrical contact blade 24 having an elongated slot 27 through which the actuator blade 25 can be reciprocated. Each of the blades has an aperture 28 and 29 through which extension 14 (FIG. 1) extends. Referring to FIGURES 1 and 3, electrical contact blade 24 has electrical contact buttons 30 and 31 disposed on each side of the blade, with the blade extending sutficiently into the cavity 22 such that its contact buttons are in spaced relation to electrical contact buttons 32 and 33 of stationary terminals 20 and 21. Each of the blades has a tab 34 and 35 extending substantially normal to the blades with each containing an aperture for carrying a magnet 36 and 37.

The material used for the fabrication of the magnets is of particular importance in the practice of the invention. The material must be one which is very dillicult to demagnetize even though the size of the magnets are small. Their size, coupled with the current running through the contact blade makes the magnets susceptible to stray fields. Preferably the magnets used in the present invention are fabricated from the anisotropic barium ferrite based permanent magnet material having a binder or matrix of rubber or other elastomeric material. The magnets are polarized such that their faces 36a and 37a are of the same polarity.

Actuator bar 18 may be depressed manually, or if desired the switch may be automatically operated by providing a cam follower surface 18a such that the switch may be operated by a cam (not shown). Actuator blade 25 may be biased such that the blade will return to the position shown in FIGURE 1 when it is in a relaxed condition. In addition, a biasing means 17 may be employed for a pressure operated switch. Means 17 comprises a rod 39 which is slidably engaged in aperture 16 and which has a slot 38 into which a spring (not shown) can be engaged such that the means 17 may be actuated in sequence with the actuator 18 when the actuator is automatically operated. Rod 39 has an extension 40 having a curved surface 40a against which actuator 18 abuts.

With reference to FIGURES 1 and 2, it can be seen that the operation of the switch depends on the polarity of the magnets. With specific reference to FIGURE 1, as magnet 37 approaches magnet 36 through movement of actuator blade 25, magnet 36 is repelled, thus causing contact blade 24 to move toward stationary terminal 20, thereby causing electrical contact 30 to be brought into contact with electrical contact 32. As shown in FIGURE 2, as magnet 37 passes by magnet 36, magnet 36 will be repelled in the opposite direction thereby causing electrical contact 31 to be brought into contact with electrical contact 33 of stationary terminal 21. Thus as magnet 37 is reciprocated past magnet 36 through the reciprocating movement of actuator blade 25 caused by the driving pressure acting against actuator 18, magnet 36 is reciprocated opposite from the movement of magnet 37, thus causing electrical contact to alternately be made between electrical terminals 20 and 21 and contact blade 24.

Thus there is described a novel magnetically operated double throw switch which operates on the principle of the repelling force of magnets as opposed to the attraction of magnets as is done in the prior art. In addition, the switch is simple in construction and therefore more reliable. Thus it will be readily apparent to those skilled in the art that this invention provides a new and useful double throw switch. Accordingly, it is contemplated that the scope of the invention is to be determined from the following appended claims.

What is claimed is:

1. A double throw snap switch comprising:

(a) a housing consisting of two elongated cup-shaped sections connected together so as to form a cavity;

(b) a pair of stationary electrical terminals extending through said housing at one end into said cavity in spaced relation,

(c) a single electrical terminal extending through the opposite end of said housing into said cavity, said single terminal consisting of a snap acting electrical contact blade and a snap acting actuator blade;

(d) electrical contacts associated with said stationary terminals and contact blade;

(e) means to actuate said acuator blade;

(f) a pair of magnets one of which is disposed on said contact blade, the other being disposed on said actuator blade;

(g) said magnets being polarized and arranged such that they repel one another as the magnet of the actuator blade is reciprocated past the magnet of the contact blade thereby causing the contact blade to alternately reciprocate between said stationary electrical terminals.

2. A double throw snap switch according to claim 1 in which said magnets are fabricated from anisotropic barium ferrite based permanent magnet material having a matrix of an elastomeric material.

3. A double throw snap switch which comprises:

(a) a housing consisting of two elongated cup-shaped sections connected together so as to form a cavity;

(b) a pair of stationary electrical terminal blades extending through said housing into said cavity in spaced parallel relation at one end of said housing;

(c) a single stationary electrical terminal extending through the other end of said housing, said single terrninal being composed of an electrical contact blade and an actuator blade, said blades being partially disposed within said housing and being contiguous from the end of said terminal to an area just inside of said housing, said contact blade being extended to an area between said spaced stationary electrical terminals;

(d) electrical contacts disposed on each side of said contact blade and being positioned in spaced relation to electrical contacts disposed on each of said spaced electrical terminals; w

(e) an actuator extending through an aperture in said lfudsing and being fixedly connected to said actuator (f) a pair of magnets one of which is disposed on said contact blade, the other being disposed on said actuator blade;

(g) said magnets being constructed and arranged such that as the actuator blade is reciprocated said actuator blade magnet is reciprocated past' said contact blade magnet and said magnets are repelled thereby causing said contact blade to be reciprocated between said spaced stationary terminals.

4. A double throw snap switch according to claim 3 in which said magnets are fabricated from an anisotropic barium ferrite based permanent magnet material having a matrix of an elastomeric material.

5. A double throw snap switch which comprises:

(a) a housing consisting of two elongated cup-shaped sections connected together so as to'form a cavity;

(b) a pair of stationary electrical terminal blades extending through said housing into said cavity in spaced parallel relation at one end of said housing;

(0) a single stationary electrical terminal extending through the other end of said housing, said single terminal being composed of an electrical contact blade and an actuator blade, said blades being partially disposed within said housing and being contiguous from the end of said terminal to an area just inside of said housing, said contact blade being extended to an area between said spaced stationary electrical terminals, said contact blade further having a slot through which said actuator blade can be reciprocated;

(d) electrical contacts disposed on each side of said contact blade and being positioned in spaced relation to electrical terminals on each of said spaced electrical terminals;

(e) an actuator extending through an aperture in said housing and being fixedly connected to said actuator blade, and having a cam follower surface;

(f) a first magnet disposed on said actuator blade, the

magnet being held in an aperture formed in a tab extending substantially normal to said blade at its end portion; I

(g) a second magnet disposed on said actuator blade, said magnet being held in an aperture formed in a tab extending substantially normal to said blade at the end of said slot through which said actuator blade is reciprocated; 1

(h) the faces of said magnets being of the same polarity such that the magnets are repelled as the actuator blade is reciprocated through said slot.

6. A double throw switch according to claim 5 in which said magnets are fabricated from an anisotropic barium ferrite based permanent magnet material having a matrix of an elastomeric material.

7. A double throw snap switch which comprises:

(a) a housing consisting of two elongated cup-shaped sections connected together so as to form a cavity; (b) a pair of stationary electrical terminal blades extending through said housing 'into said cavity in spaced parallel relation at one end of said housing;

(c) a single stationary electrical terminal extending through the other end of said housing, said single terminal being composed of an electrical contact blade and an actuator blade, said blades being partially disposed within said housing and being contiguous from the end of said terminal to an area just inside of said housing, said contact blade being extended to an area between said spaced stationary electrical terminals;

(d) electrical contacts disposed on each side of said pontact blade and being positioned in spaced relation to electrical contacts disposed on each of said spaced electrical terminals;

(e) an actuator extending through an aperture in said housing and being fixedly connected to said actuator blade;

(f) biasing means for said actuator extending through an aperture in said housing;

(g) a pair of magnets one of which is disposed on said contact blade, the other being disposed on said actuator blade;

(h) said magnets being constructed and arranged such that as the actuator blade is reciprocated said actuator blade magnet is reciprocated past saidvcontact blade magnet and said magnets are repelled thereby causing said contact blade to be reciprocated between said spaced stationary terminals.

8. A double throw snap switch according to claim 7 in which said biasing means comprises a spring biased rod slidably engaged in said aperture and which has an extension having a curved surface against which said actuator abuts.

9. A double throw switch according to claim 7 in which said magnets are fabricated from an anisotropic based permanent magnet material having a matrix of an elastomeric material.

10. A snap switch comprising at least one fixed electrical contact, a cantilever mounted snap acting electrical contact blade including at least one electrical contact at a free end thereof for engaging and disengaging with said fixed contact, means for actuating said blade, and at least one magnet carried by said blade at said free end and at least one magnet carried by said means for actuating said blade, said magnets polarized whereby said magnet carried by said blade is repelled by said magnet carried by said actuating means as said magnet carried by said actuating means is reciprocated past the magnet of said blade.

11. A snap switch according to claim 10 wherein there is a pair of said fixed electrical contacts in spaced relationship and said blade is movable between said contacts.

12. A snap switch according to claim 11 wherein said actuator means includes an actuator blade extending through an aperture in said blade.

13. A snap switch according to claim 12 wherein said actuator blade is responsive to a cam follower means responsive to a cam means.

14. A snap switch according to claim 13 wherein said cam follower means is additionally responsive to spring biasing means.

15. A snap switch according to claim 10 wherein said magnets are fabricated from an isotropic barium ferrite based permanent magnet material having a matrix of an elastomeric material.

References. Cited UNITED STATES PATENTS 2,520,935 9/1950 Hubbell.

BERNARD A. GILHEANY, Primary Examiner. R. N. ENVALL, JR., Assistant Examiner.

U.S. Cl. X.R. 200-67; 335188 

